Edward B. Lee, MD PhD - US grants

DESCRIPTION (provided by applicant): This proposal describes a 5 year career development plan for Dr. Edward B. Lee to serve as a transition to successful independent physician-scientist. Dr. Lee has completed his clinical training in Anatomic Pathology and Neuropathology at the University of Pennsylvania, and will now foster a collaborative research project with the resources of both Endocrinology and Neuropathology. This project will provide superb training for Dr. Lee to develop into an independent physician-scientist. The project will be mentored Dr. Rexford S. Ahima of the Institute for Diabetes, Obesity and Metabolism, and co-mentored by Dr. John Q. Trojanowski, Director of the Alzheimer's Disease Core Center and the Institute on Aging. This grant will provide the protected time so that Dr. Lee will gain expertise in metabolism research with formal coursework and numerous scientific seminars and meetings. The environment at the University of Pennsylvania provides the unique opportunity to parlay its expertise in aging, metabolic disorders and neurodegenerative diseases to conduct the proposed projects, and to provide Dr. Lee with the training required to proceed towards a successful academic career. Aging and obesity are both affecting the American population at record levels, and both aging and obesity are risk factors for Alzheimer's disease (AD). Although, it is known that mid-life obesity increases the risk of AD and that diet-induced obesity promotes amyloid deposition in transgenic mouse models, there is little mechanistic insight into how obesity adversely affects the aging brain. Leptin is a hormone secreted by adipose tissue with profound effects on metabolism by acting on the brain. Leptin levels are increased due to aging and obesity, and both conditions results in central leptin resistance. Leptin inhibits cerebral amyloid in transgenic mouse models, but our understanding of this effect is hampered in part because leptin has both direct effects on neuronal signaling pathways and indirect effects on metabolism. The hypothesis of this proposal is that leptin triggers neuronal signaling pathways which protect against cerebral amyloid pathology. The direct effects of leptin are difficult to ascertain in mouse models of leptin deficiency due to the numerous secondary metabolic effects which complicate interpretation including obesity, diabetes, hyperlipidemia and neuroendocrine dysfunction. To circumvent this issue, Dr. Lee will perform innovative studies to determine leptin's effects controlling for major shifts in body weight. Transgenic mice that develop cerebral amyloid will be treated with physiologic doses of leptin controlling for changes in body weight. Second, the effects of acute leptin treatment on downstream signaling pathways and A2 amyloid peptide levels will be assessed in live animals. Finally, the behavioral and pathologic effects of a leptin receptor mutation which enhances leptin receptor signaling will be determined. These studies will provide mechanistic insights into the role of leptin in AD pathogenesis, and provide the basis for future drug or biomarker development. PUBLIC HEALTH RELEVANCE: The aging population and the alarming increase in obesity rates will have profound effects on the health of the American population due to aging and obesity related diseases. The known link between mid-life obesity and late-life dementia is poorly understood. The role of the hormone leptin which is altered in obesity and aging will be studied in terms of its effects on Alzheimer's disease dementia.

? DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) are two related neurodegenerative diseases which share overlapping clinical, pathologic and genetic features. The ALS/FTD spectrum of diseases is uniformly fatal, and there is neither treatment nor cure. The endogenous mechanisms which exacerbate or mitigate disease progression in these diseases are not clearly understood. However, a mutation within the C9orf72 gene has been discovered as the most common genetic cause of ALS/FTD. The mutation consists of a hexanucleotide repeat expansion which has been proposed to lead to the accumulation of toxic RNA and protein species. C9orf72 mutations are also associated with C9orf72 promoter hypermethylation in a subset of mutation carriers. Promoter hypermethylation appears to protect against many of the molecular aberrations associated with the C9orf72 mutation including DNA repeat instability, toxic RNA accumulation, dipeptide repeat protein accumulation and cellular vulnerability to stress. C9orf72 methylation also predicts prolonged disease duration, maintenance of grey matter, and preservation of memory function in FTD patients with the C9orf72 mutation. Based on these findings, the hypothesis of this proposal is that epigenetic editing of mutant C9orf72 can modulate disease pathogenesis. To test this hypothesis, I have developed a novel method of introducing or removing CpG methylation within the endogenous genome, and propose three specific aims to (1) determine the molecular mechanisms and specificity of targeted epigenetic editing, (2) introduce C9orf72 hypermethylation in patient-derived iPS cells as a proof-of-concept study to show that epigenetic targeting can be therapeutic, and (3) develop improved models of disease by demethylating the C9orf72 promoter in iPS cells with large C9orf72 repeat expansions. These studies will bring to reality the possibility of epigenetic editing as a means of modulating neurodegenerative disease phenotypes, and will highlight the utility of a novel epigenetic editing technique that is broadly applicable across many disciplines.

Project Summary Amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) are two related neurodegenerative diseases which share overlapping clinical, pathologic and genetic features. The ALS-FTD spectrum of diseases is uniformly fatal, and there is neither treatment nor cure. There is a remarkable convergence of pathologic and genetic data which indicate that abnormal RNA metabolism is linked to neurodegeneration in ALS and FTD. The overall goal of this proposal is define the molecular neuropathology of ALS and FTD using human brain tissue. Understanding the molecular aberrations associated with specific brain pathologies will reveal insights into the molecular pathogenesis of ALS/FTD. Novel methods are presented in which pathologic proteins or neurons are isolated from human brain for deep molecular analysis. Two specific aims are proposed which will (1) determine the molecular composition of pathologic TDP-43 protein inclusions, and (2) identify the abnormalities in RNA processing due to the loss of normal nuclear TDP- 43 protein. These studies will further our understanding of TDP-43 proteinopathies by using highly innovative techniques to study human brain tissue with advanced molecular techniques.

Abstract This R13 grant application is to support the 94th Annual Meeting of the American Association of Neuropathologists (AANP), to be held at Hyatt Regency Louisville, KY on June 7 through 10th, 2018. The National Plan to Address Alzheimer's Disease calls for the prevention and treatment of Alzheimer's disease and related dementias (ADRD) by 2025. Critical to this goal is the role of neuropathologists in describing the neuropathology associated with ADRD and aging. Towards this end, the annual AANP meeting provides the most efficient means to disseminate the latest developments in ADRD and aging-related neuropathologies. The 2018 AANP meeting will have a theme of ?Neuropathologic Hetereogeneity in Dementia and Aging? in order to broadcast the newest entities and concepts. AANP aims to attract the most promising neuropathology trainees towards a career focused on ADRD by providing travel awards, reducing registration costs, formal incorporation into the planning process, and encouraging the participation of persons with disabilities, underrepresented minorities and women. The long term impact of this meeting will be to improve the evaluation and diagnosis of ADRD and aging-related neuropathologies across the nation, to enhance cross- institutional collaborations, and to maintain a healthy pipeline of neuropathology trainees interested in neurodegenerative disease pathology.

Rare genetic causes of human disease have the potential to reveal mechanistic insights into more common sporadic disease. Rare mutations in MAPT, the gene for the neuronal cytoskeleton tau protein, cause familial tauopathies that typically manifest clinically as frontotemporal dementia. Tauopathies are a group of fatal neurologic diseases, including Alzheimer's disease, where neurodegeneration is the result of accumulation of pathologic tau protein aggregates in the form of neurofibrillary tangles, Pick bodies, or glial inclusions. MAPT mutations are the only known cause of autosomal dominant primary tauopathy. We have identified a previously undescribed autosomal dominant form of frontotemporal degeneration with tau inclusions associated with a novel genetic mutation in a highly conserved, essential gene. We propose three specific aims to understand the basic molecular mechanisms by which this gene mutation leads to tau pathology. We will perform studies to determine how this genetic mutation alters tau interactions and aggregation in vitro and in cultured cells. We will extend these findings to determine the effects of this gene mutation on endosomal function to determine whether this gene mutation affects intracellular seeding of tau aggregates. Finally, we will test the effects of this genetic mutation of tau transmission in mice to determine whether this gene mutation enhances tau virulence in vivo. Together, these mechanistic studies will elucidate basic mechanisms which promote tau pathology, thereby validating a novel therapeutic target for future development of novel anti-tau therapies.

Abstract This R13 grant application is to support a pre-meeting educational workshop to be held prior to the Annual Meeting of the American Association of Neuropathologists (AANP). The National Plan to Address Alzheimer's Disease calls for the prevention and treatment of Alzheimer's disease and related dementias (ADRD) by 2025. Critical to this goal is maintaining, developing and supporting neuropathology trainees to fill the dearth of academic neuropathologists dedicated to ADRD and aging research. Towards this end, the annual AANP meeting represents a national focal point for neuropathology trainees. Starting at the June 2020 AANP meeting in Monterey, CA, this R13 grant will support a targeted career development and scientific pre-meeting workshop for a cohort of 20 neuropathology trainees. A three year longitudinal program, focusing on the (1) expectations and barriers to an academic neuropathology career, (2) funding and grantsmanship, and (3) strategies for building a successful research career. This workshop will attract the most promising neuropathology trainees towards a career focused on ADRD by offsetting travel and registration costs, in addition to supporting trainee involvement with the meeting planning process, and encouraging the participation of underrepresented minorities, women, and persons with disabilities. The long term impact of this meeting will be to maintain a healthy pipeline of neuropathology trainees dedicated to ADRD research in support of the national plan to prevent and treat ADRD.

Frontotemporal degeneration (FTD) is an understudied clinical neurodegenerative condition even though it is the most common cause of dementia after Alzheimer?s disease (AD) in people <65 years old. The most common frontotemporal lobar degeneration (FTLD) pathology associated with FTD is TDP-43 proteinopathy known as FTLD-TDP with the other major class consisting of cases of FTLD-Tau. Moreover, several autosomal dominant gene mutations and disease-associated genetic variants have been associated with FTD. Aside from genetic mutations that are associated with specific subtypes of FTLD, there are no known biomarkers for the vast majority of FTD patients with sporadic disease that can reliably distinguish patients with FTLD-TDP histopathology from those with FTLD-Tau pathology, nor from patients who present with clinical FTD but are atypical variants of pathological AD. The Neuropathology & Genetics Core will work with other cores and projects to improve our understanding of the TDP-related degeneration of multilevel neural networks examined in this Program Project Grant (PPG). This core will perform a comprehensive post- mortem brain autopsy examination to provide a definitive autopsy diagnosis for cases followed in the clinical core B and the neuroimaging core C. We will also perform a comprehensive genetic analysis of cases and controls to identify disease causing and associated genetic changes. Additional activities will including banking of tissues and nucleic acids, providing tissues, data and expertise to other investigators, and conducting RNA expression studies to further the aims of the research projects in the PPG.

Dementia is associated with selective degeneration of microscopic and macroscale neuronal networks resulting in heterogeneous clinical features. Data from human neuropathology and experimental models support the hypothesis that neurodegenerative disease pathologies spread through selectively vulnerable neuronal networks. Frontotemporal dementia can manifest clinically as behavioral variant of FTD (bvFTD) or primary progressive aphasia (PPA). Both clinical phenotypes can be associated with the accumulation of protein aggregates in affected brain regions composed of either TDP-43 or tau protein. Understanding how networks degenerate in fronototemporal dementia is important in terms of understanding the progression of disease as it relates to variable clinical and pathologic subtypes. The goal of this project is to perform single cell RNA sequencing (scRNAseq) of key regions that degenerate in frontotemporal lobar degeneration to identify cellular-level molecular networks that are specifically altered due to TDP-43 versus tau pathology in behavioral variant frontotemporal dementia and primary progressive aphasia. Novel bioinformatics approaches will be applied to scRNAseq datasets to identify neuronal cell types and molecular networks which are selectively vulnerable in frontotemporal dementia clinicopathologic subtypes.

BRAIN BANK CORE SUMMARY Although we have made great progress in gaining a deeper understanding of traumatic brain injury (TBI) related neurodegeneration (TReND), we have not gotten to the point where appropriate thereapeutics are available. This is, in part, due to the limited number of suitable human brain tissue samples available to research institutions. In fact, there exists only one human brain tissue archive dedicated to TBI samples, located at the University of Glasgow in Scotland, UK. In order to overcome this lack of resource, the Brain Banking Core of CONNECT-TBI will bring together nine participating banks that will be capable of providing existing tissue samples from almost 2000 acute and over 800 chronic TBI cases. This Brain Banking Core will establish a unique and comprehensive central archive of all existing TBI related autopsy tissue, that will include a broad inventory of all available tissue and associated clinical data. The CONNECT-TBI Expert Consensus Group members will assess and score digitally scanned images. Within this Brain Banking Core will be high quality, robust clinical datasets and digitized histology sections that will not only support the Research Projects within this proposal, but support approved, external, researcher led studies. Furthermore, the BBC will establish a tissue donation network from all participating centers that will significantly enhance the number of available tissue samples. In all efforts, the Brain Banking Core will optimize best practice protocols and will ensure adherence to strict tissue handling, staining, and scanning protocols. Finally, the Brain Bank Core will facilitate the dissemination all TBI-related samples and data in support of the Research Projects which comprise the mission of CONNECT-TBI.

Neuropathology Core: Abstract Nearly all neurodegenerative disorders are characterized by progressive accumulations of pathological deposits of disease protein aggregates within cells, blood vessels or in the neuropil. These deposits are the signature CNS lesions that define these disorders as exemplified by the amyloid plaques and neurofibrillary tangles required for the postmortem diagnosis of Alzheimer's disease (AD) and related disorders (ADRD). However, Lewy bodies (LBs) and/or TDP-43 inclusions occur in ~70% of AD patients, as are other neuropathologies including aging related tau astrogliopathy (ARTAG), hippocampal sclerosis, and cerebrovascular disease. Other non-AD dementing illnesses are associated with a diverse spectrum of neuropathologic diagnoses including various ?-synucleinopathies and frontotemporal lobar degeneration. A major focus of this NP Core is to define the full spectrum of co-morbid protein aggregate pathologies in the aging brain. A comprehensive post-mortem brain examination of individuals followed longitudinally in the Clinical Core provides definitive classification of the underlying neuropathology using standardized criteria in addition to the exhaustive documentation of co-morbid neurodegenerative disease pathologies in each case irrespective of clinical phenotype. Fixed and frozen tissues are banked and distributed to investigators to further both clinicopathologic and basic research studies on AD/ADRD. Neuropathology data is obtained in all cases which is transmitted to the National Alzheimer?s Coordinating Center in collaboration with the DMS Core. The NP Core also coordinates with the Neuroimaging Core to facilitate high resolution post-mortem MRI and to establish a digital histopathology library. The NP Core also provides advice and support to investigators including trainees supported by the Research Education Component to foster safe and informative human biosamples research. Thus, this NP Core is a vital component of the Penn ADRC in defining the complexity and breadth of neuropathologic change in ADRC subjects in support of its mission to increase research and education on AD/ADRD across the continuum from normal aging to dementia with the goal of identifying the causes of and cures for AD/ADRD.